A threshold problem in post processing of the output stream from a keyboard, character reader, or voice analyzer is presented by the necessity of executing a quick comparison of the output word with a dictionary of acceptable words and generating a signal indicating the presence or absence of a correctly spelled word. An ancillary problem is created by the need to store a dictionary of words large enough to be meaningful and useful while not requiring so much storage space that the system becomes economically unfeasible.
A solution to the latter problem is disclosed in U.S. Pat. No. 3,995,254 entitled "Digital Reference Matrix For Word Verification", issued Nov. 30, 1976, to W. S. Rosenbaum. In the Rosenbaum patent a word vectorization system is disclosed wherein each dictionary word is represented as a vector having a magnitude and unique angle. The magnitudes are used as addresses to access the angles stored in a memory. It was shown that this technique provides a significant reduction in required storage over storing the characters of the same number of dictionary words.
However, implementation of the word vectorization technology described in the Rosenbaum patent in mini-computers has been shown to be of limited value. The reason being that one characteristic of the mini-computer is the lack of complex mathematics function capability such as multiplication, division, square root, logarithms, and trigonometry. Since the word vectorization technology described in the Rosenbaum patent extensively employs these complex mathematics functions, methods for simulating these functions must be utilized. The simulation methods heretofore used have greatly reduced the computing efficiency of the mini-processor.